JP4168482B2 - Binder for printing ink - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing ink binder. It is particularly suitable for a special gravure ink binder.
[0002]
[Prior art]
In recent years, various types of plastic films as packaging materials have been developed as packaging contents become more complex and packaging technology has been advanced, and as a result, films that can be adapted to the contents are appropriately selected and used. Became.
[0003]
As such a binder for a printing ink for a plastic film, a polyurethane resin is awarded because of its excellent adhesiveness. However, printing inks that use polyurethane resin as a binder have excellent adhesion to polyester films and nylon films alone, but they do not adhere to polyolefin films such as polyethylene films and polypropylene films that are general purpose films. It was not enough.
[0004]
[Problems to be solved by the invention]
An object of this invention is to provide the binder for printing inks excellent in the adhesiveness with respect to various plastic films, such as a polyester film, a nylon film, and a polyolefin film.
[0005]
[Means for Solving the Problems]
In light of the above technical background, the present inventors have intensively studied to solve the problems of the prior art. As a result, a compound represented by the following general formula (1) is used as a chain extender component. It has been found that the above-mentioned problems can be solved by using a polyurethane resin used in a proportion of 5 to 60% by weight as a binder for printing ink, and the present invention has been completed.
[0006]
That is, the present invention relates to a binder for a printing ink comprising a polyurethane resin obtained by reacting a polymer polyol, a diisocyanate compound and a chain extender as main components, and the general formula (1):
[0007]
[Chemical 2]
[0008]
(Wherein n represents an integer of 0 to 6 and R represents an alkyl group or an aryl group having 1 to 18 carbon atoms.) 5-60 wt% of the chain extender component. The present invention relates to a printing ink binder.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The polyurethane resin used as the binder for printing ink of the present invention is obtained by reacting a polymer polyol, a diisocyanate compound and a chain extender as main components, and the chain extender component is represented by the general formula (1). Is used.
[0010]
Examples of the alkyl group represented by R in the general formula (1) include a linear or branched alkyl group or a cycloalkyl group. Examples of the aryl group include a phenyl group. Such R is preferably a cycloalkyl group or a phenyl group because of good blocking resistance.
[0011]
Specific examples of the compound represented by the general formula (1) include N-methylhydrazine, N-ethyl-ethylenediamine, N-methyl-1,3-propanediamine, and N-hexyl-1,3-propane. Diamine, N-lauryl-1,3-propanediamine, N-stearyl-1,3-propanediamine, N-ethylhexamethylenediamine, N-cyclohexyl-1,3-propanediamine, N-phenyl-ethylenediamine and the like A typical example.
[0012]
In chain extender component, the proportion of the compound represented by the general formula (1), when the proportion of the compound represented by one general formula (1) is increased, the viscosity of the resulting polyurethane resin is lowered, blocking Therefore, it is necessary to make it about 60% by weight or less of the chain extender component, and it is preferable to make it 50% by weight or less. Further, if the ratio of the compound represented by the general formula (1) in the chain extender component is small, the effect of improving the adhesiveness is not sufficient, so that the extender component needs to be 5% by weight or more .
[0013]
Examples of the chain extender that can be used in combination with the compound represented by the general formula (1) include polyamines having an average molecular weight of less than 500. Specifically, aliphatic polyamines (ethylenediamine, propylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine, etc., 2-hydroxyethylethylenediamine), alicyclic polyamines (isophoronediamine) Dicyclohexylmethane-4,4′-diamine, isopropylidene dicyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, etc.), aromatic polyamines (xylylenediamine, etc.), hydrazine, dihydrazide, etc. can give.
[0014]
In the present invention, a polymerization terminator can be used together with the chain extender. Examples of the polymerization terminator include monoamines such as monoethylamine, n-propylamine, n-butylamine, di-n-propylamine and di-n-butylamine, and hydroxyl monoamines such as monoethanolamine and diethanolamine. It is done.
[0015]
As the polymer polyol component which is another component of the polyurethane resin of the present invention, various compounds used as the polymer polyol of the polyurethane resin can be used. Specifically, polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene diol (block and / or random) polytetramethylene ether glycol, which are polymers such as ethylene oxide, propylene oxide, and tetrahydrofuran Ethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, hexanediol, 1,8-octamethylenediol Aliphatic diols such as bis (hydroxymethyl) cyclohexane, m- and p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 4,4'-bis (2-hydride) Diols having a cyclic group such as xyloxy) -diphenylpropane, aromatic dicarboxylic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, Various known polyester polyols obtained by dehydration condensation of aliphatic dicarboxylic acids such as azelaic acid and sebacic acid; polyester polyols obtained by ring-opening polymerization of cyclic ester compounds; other polycarbonate polyols, polybutadiene glycols, etc. The polymer polyol is exemplified.
[0016]
As described above, the molecular weight (number average molecular weight by hydroxyl value measurement) of various polymer polyols is usually about 500 to 5000, more preferably 700 or more, and more preferably 4000 or less.
[0017]
In addition, as the diisocyanate compound, an aliphatic diisocyanate having 2 to 12 carbon atoms (excluding carbon in the NCO group), an alicyclic diisocyanate having 4 to 15 carbon atoms, an araliphatic diisocyanate having 8 to 12 carbon atoms, and a carbon number. 6-20 aromatic diisocyanates and modified products thereof (carbodiimide group, uretdione group, uretoimine group, urea group, burette group and / or isocyanurate group-containing modified product) and the like can be used. Specific examples of such a diisocyanate compound include aliphatic diisocyanates such as butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate; Cycloaliphatic diisocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate; xylylene diisocyanate, m-tetramethyl Aromatic aliphatic diisocyanates such as xylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate Typical examples include (MDI), polyphenylmethane polyisocyanate, modified MDI such as carbodiimide modification, and aromatic diisocyanates such as 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and tolylene diisocyanate.
[0018]
The method for producing the polyurethane resin of the present invention is not particularly limited. For example, a urethane prepolymer having both terminal isocyanate groups is prepared from a polymer polyol component and an excess diisocyanate compound, and further, a chain extender and a polymerization termination used as necessary. Either a prepolymer method in which an agent is reacted or a one-shot method in which a polymer polyol component, a diisocyanate compound, a chain extender, and a polymerization terminator used as necessary are reacted at a time can be employed. The prepolymer method is preferred because of ease of production. When the polyurethane resin of the present invention is produced by the prepolymer method, an amine dropping method in which a chain extender and a necessary polymerization terminator are added to the prepolymer, or a prepolymer is added in the chain terminator and a necessary polymerization terminator. Any of the prepolymer dropping methods can be employed. When the amine dropping method is used, the method for adding amines is not limited, and either batch charging or two or more divided chargings may be used. In the production of the urethane prepolymer in the prepolymer method, the equivalent of the isocyanate group of the diisocyanate compound is usually 1.1 to 5 equivalents, preferably 1.2 equivalents or more, based on 1 equivalent of the hydroxyl group of the polymer polyol. The equivalent or less is preferable.
[0019]
The polyurethane resin of the present invention is preferably reacted with a chain extender and, if necessary, a polymerization terminator so that the amine value is about 0.3 to 30 (KOHmg / g). Usually, in the case of the prepolymer method, when the amount of the isocyanate group of the urethane prepolymer is 1 gram equivalent, the total of amino groups in the chain extender and the polymerization terminator used as necessary is 1 to 2 gram equivalent. Is preferable. It should be noted that when the amino group is less than 1 gram equivalent, the solvent resistance tends to decrease, and when the amino group exceeds 2 g equivalent, the chain extender remains unreacted in the polyurethane resin and produces a bad odor. .
[0020]
The production of the polyurethane resin in the present invention is carried out in the presence or absence of a solvent. Solvents used include aromatic solvents (benzene, toluene, xylene, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), alcohol solvents (methanol, ethanol, isopropanol, n-butanol, etc.), ketone solvents Solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ether solvents (tetrahydrofuran, etc.), polyhydric alcohol solvents (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), amide solvents (dimethylformamide, etc.), sulfoxide Examples thereof include a system solvent (such as dimethyl sulfoxide) and a mixed solvent of two or more thereof. Among these, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, tetrahydrofuran, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and a mixture of two or more thereof are preferable. It is a solvent.
[0021]
The amount of solvent used is such that the weight ratio of polyurethane resin / solvent is in the range of 100/0 to 10/90, preferably 80/20 to 20/80.
[0022]
The number average molecular weight of the polyurethane resin is about 5000 to 100,000. The number average molecular weight is preferably 8000 or more, and preferably 80000 or less.
[0023]
In addition, the resin which comprises the binder for printing inks of this invention may use the said polyurethane resin independently, and may use together with the other resin currently used as a binder for printing inks as needed. Examples of other combined resins include polyurethane resins other than the present invention, polyamide resins, nitrocellulose, polyacrylates, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, chlorinated polypropylene, styrene butadiene rubber, epoxy resins, rosin Resin, ketone resin and the like. When other resins are used in combination, the amount is within the range not impairing the object of the present invention, and is usually 50% by weight or less in the solid content of the binder.
[0024]
The binder for printing ink of the present invention is usually a solution of a solvent as exemplified above for the resin component containing the polyurethane resin. The resin concentration of the present invention is usually 10 to 90% by weight, preferably 20% by weight or more, and preferably 80% by weight or less, based on weight. The viscosity is usually 50 to 500,000 cP / 20 ° C., preferably 100 cP / 20 ° C. or more, and preferably 100000 cP / 20 ° C. or less.
[0025]
The printing ink binder of the present invention is used for the preparation of printing ink by the same method as the conventional printing ink binder. That is, a printing ink can be produced by adding a pigment and, if necessary, an additive such as a pigment dispersant to the printing ink binder of the present invention and kneading the mixture using a normal ink production apparatus such as a ball mill.
[0026]
An example of the formulation of a printing ink using the ink binder of the present invention is as follows. Usually, the printing ink binder (solid content) of the present invention is about 5 to 30% by weight, and the pigment is 5 to 40% by weight. %, Solvent (including the solvent in the printing ink binder) about 40 to 80% by weight, and an appropriate amount of additives.
[0027]
When the printing ink binder of the present invention is used, it may be used as a one-component ink, but it can also be used as a two-component printing ink in combination with a polyisocyanate curing agent. Examples of polyisocyanate curing agents include adducts synthesized from 1 mol of trimethylolpropane and 3 mol of 1,6-hexamethylene diisocyanate, tolylene diisocyanate or isophorone diisocyanate; 1,6-hexamethylene diisocyanate, or isophorone diisocyanate. Isocyanurate group-containing trimer synthesized by cyclic trimerization of isocyanurate groups; partial burette reactant synthesized from 1 mol of water and 3 mol of 1,6-hexamethylene diisocyanate, and a mixture of two or more of these Is preferred. When used as a two-component printing ink, the addition amount of the polyisocyanate curing agent is usually about 0.5 to 10% by weight based on the ink.
[0028]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the binder for printing inks excellent in the adhesiveness with respect to various plastic films, such as a polyester film, a nylon film, and also a polyolefin film, can be provided. In addition, the printing ink binder of the present invention is excellent in adhesiveness, and also excellent in boil and retort suitability required when laminated by improving the performance of the packaging material.
[0029]
The reason why the printing ink binder of the present invention exhibits excellent adhesion to various plastic films is not clear, but in polyurethane resins used as printing ink binders, diisocyanates generally referred to as hard segments A compound consisting of a compound, a chain extender, and a polymerization terminator used as needed (whereas a part consisting of a polymer polyol is generally referred to as a soft segment) can be substituted with a specific alkyl by the compound represented by the general formula (1). An amino group having a group or an aryl group is introduced, and the amino group having such a specific substituent is considered to have some great effect in improving the adhesion to various plastic films.
[0030]
【Example】
EXAMPLES Hereinafter, although a manufacture example, an Example, and a comparative example are given and this invention is further demonstrated, this invention is not limited to these examples. In each example, parts and% indicate parts by weight and% by weight, respectively.
[0031]
Production Example 1
A four-necked flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube was charged with 622.6 parts of poly-3-methylpentaneadipatediol having a molecular weight of 5000 and 77.4 parts of isophorone diisocyanate, and the mixture was heated to 100 ° C. under a nitrogen stream. The mixture was reacted for 6 hours to produce a prepolymer, and then 300.0 parts of methyl ethyl ketone was added to obtain 1000 parts of a uniform solution of urethane prepolymer. Next, a mixture comprising 19.1 parts of isophorone diamine, 2.5 parts of di-n-butylamine, 19.1 parts of N-cyclohexyl-1,3-propanediamine, 852.1 parts of methyl ethyl ketone and 576.1 parts of isopropyl alcohol was obtained. It added to the said urethane prepolymer solution, and was made to react at 50 degreeC for 3 hours. The polyurethane resin solution A thus obtained had a resin solid content concentration of 30%, an amine value of 3, and a number average molecular weight of 25,000.
[0032]
Production Example 2
Using the same reactor as in Production Example 1, 1000 parts of the urethane prepolymer solution similar to Production Example 1 was prepared, and then 30.0 parts of isophoronediamine, 0.4 parts of di-n-butylamine, N-methyl-1 , 3-propanediamine 7.5 parts, methyl ethyl ketone 847.9 parts and isopropyl alcohol 574.0 parts were added and reacted at 50 ° C. for 3 hours. The polyurethane resin solution B thus obtained had a resin solid content concentration of 30%, an amine value of 6, and a number average molecular weight of the polyurethane resin of 18,000.
[0033]
Production Example 3
Using the same reactor as in Production Example 1, 1000 parts of the urethane prepolymer solution similar to Production Example 1 was prepared, and then 39.8 parts of isophorone diamine, 0.3 part of di-n-butylamine, N-phenyl-ethylenediamine. A mixture consisting of 2.1 parts, 854.5 parts of methyl ethyl ketone and 577.2 parts of isopropyl alcohol was added and then reacted at 50 ° C. for 3 hours. The polyurethane resin solution C thus obtained had a resin solid content concentration of 30%, an amine value of 4, and a polyurethane resin number average molecular weight of 27,000.
[0034]
Production Example 4
Using the same reactor as in Production Example 1, 1000 parts of the urethane prepolymer solution similar to Production Example 1 was prepared, and then 43.6 parts of isophoronediamine, 0.2 part of di-n-butylamine, 857.0 parts of methyl ethyl ketone. And a mixture consisting of 578.5 parts of isopropyl alcohol and then reacted at 50 ° C. for 3 hours. The polyurethane resin solution D thus obtained had a resin solid content concentration of 30%, an amine value of 5, and a number average molecular weight of the polyurethane resin of 22,000.
[0035]
Production Example 5
Using the same reactor as in Production Example 1, 1000 parts of a urethane prepolymer solution similar to Production Example 1 was prepared, and then 33.8 parts of isophoronediamine, 3.2 parts of di-n-butylamine, and 3.methylenediamine. A mixture consisting of 8 parts, 852.4 parts of methyl ethyl ketone and 576.0 parts of isopropyl alcohol was added and then reacted at 50 ° C. for 3 hours. The polyurethane resin solution E thus obtained had a resin solid content concentration of 30%, an amine value of 3, and a polyurethane resin number average molecular weight of 23,000.
[0036]
Examples 1-3 and Comparative Examples 1-2
30 parts of titanium white (rutile type), 50 parts of the polyurethane resin solutions A to E obtained in Production Examples 1 to 5, 10 parts of toluene and 10 parts of isopropyl alcohol were each kneaded with a paint shaker and printed in white An ink was prepared. To the obtained white printing ink, 35 parts of toluene and 15 parts of isopropyl alcohol were further added to adjust the viscosity, and the five-point white ink shown in Table 1 was prepared.
[0037]
(Adhesion test)
The obtained white ink was printed on one side of a stretched polypropylene film (OPP) and a nylon film (NY) using a bar coater (No. 4) and dried at 40 to 50 ° C. to obtain a printed film. It was. Then, an 18 mm wide adhesive tape (trade name (trademark) cello tape) manufactured by Nichiban Co., Ltd. is pasted on the printing surface of the obtained printing film, and one end of this adhesive tape is rapidly applied in a method perpendicular to the printing surface. The state of the printed surface when peeled off was observed. The case where the ink on the printing surface was not peeled off was evaluated as “◯”, the case where 40% or more remained was “Δ”, and the case where less than 40% remained was evaluated as “X”. The results are shown in Table 1.
[0038]
[Table 1]

Claims (4)

In a binder for printing ink comprising a polyurethane resin obtained by reacting a polymer polyol, a diisocyanate compound and a chain extender as main components, the chain extender component is represented by the general formula (1):
(Wherein n represents an integer of 0 to 6 and R represents an alkyl group or an aryl group having 1 to 18 carbon atoms) 5-60 wt% of the chain extender component. Binder for printing ink.  The printing ink binder according to claim 1, wherein R in the general formula (1) is a cycloalkyl group or a phenyl group. The printing ink binder according to claim 1 or 2, wherein n in the general formula (1) is 2 or 3.  4. The printing ink binder according to claim 1, wherein the polyurethane resin has an amine value of 0.3 to 30.